5-6 A prototype of a silicon electret condenser microphone

Abstract

Toward an ultraminiature high-performance microphone for next generation, we are studying a silicon electret condenser microphone. Recently we investigated etching and electric characteristics of silicon nitride/oxide electret film, and determined deposition condition of the nitride film. We also developed a fabrication process of electret transducer. A prototype transducer showed sufficiently flat frequency response in audio frequency range.